Our golf course like most has several miles of piping underground leading from our pumpstation located behind the 11th green to the 500+ sprinkler heads. All of our underground piping is PVC and varies from 6" near the pumphouse to 2" around the greens and tees.
Our pumpstation has two 75 horsepower pumps for general pumping and a 5 horsepower pump for maintaining the pressure or running one or two heads. We keep the pressure in the pipes at 80psi when we are not watering to reduce stress on our pipes but the pressure slowly increases based on flow rates to 110psi when pumping over 200 gallons per minute up to the 1400 gallons per minute capacity of the station. We have seen our number of leaks decrease by over 50% by keeping the pressure lower when not watering.
Leaks can happen due to improper glue fittings, defective parts, stress from the ground moving due to freeze / thaw or dry / wet periods and water hammer. We blow out all the pipes with compressed air each fall so breaks from the pipes freezing are very rare.
This particular repair on hole 17 was made for the fourth time which is rare. We average 4 leaks a year and in my 16 years we repaired 2 of them twice and now this one 4 times.
This section of pipe is a 6" mainline with a 4" tee leading up hole 17. The first time we had a glue fitting leaking and found the entire area encased in concrete. We chiseled out the area to be repaired and being it was the middle of summer took the easy route and repaired only that section. The repair was difficult because the pipes did not line up close at all so we had to pry quite a bit to get it all together.
That lasted a couple weeks when the stress was too strong and the new glue fitting failed.We made the decision due to the pipes not lining up to dig up both sides of the pipe, rent a jackhammer and air compressor to break out the concrete and replace the entire area. We made what we thought was a good repair and it lasted a year when our new 6" tee cracked either through the ground moving, a defect or the pipes moving due to water hammer even though we had properly installed thrust blocks.
We made our repairs and this time used more gasket fittings rather than glue to allow the pipes a little flex and we thrust blocked them again to ensure we would not have problems. Well that lasted two years when the tee split again during the recent dry spell leading us to think the pipes are moving as the clay dries and re-wets.
Our irrigation consultant Tom Emmerich suggested we use a ductile iron tee and fittings to take the stress better than the PVC fittings. So $1,100 and a lot of digging later the repair was made and we are up and running again. I hope this is the last time we see this stretch of pipe.
Working in slop is never fun!
The PVC fittings have been replaced with a ductile iron tee and
couplers to give it more strength. After this picture we added thrust blocks and
filled in the hole.
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